• Title/Summary/Keyword: prompt engineering

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A Study on Prompt Engineering Techniques based on chatGPT (ChatGPT를 기반으로 한 프롬프트 엔지니어링 기법 연구)

  • Myung-Suk Lee
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2023.07a
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    • pp.715-718
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    • 2023
  • 본 연구는 ChatGPT 모델의 특성과 장점을 활용하여 프롬프트 엔지니어링 기법을 연구하고자 하였다. 프롬프트는 엔지니어가 원하는 결과를 잘 얻을 수 있도록 하는 것이 목표이기 때문에 ChatGPT와 프롬프트 엔지니어링의 상호작용과 효과적인 프롬프트 엔지니어링 기법을 개발할 필요가 있다. 연구 방법으로는 ChatGPT에 대한 학습자 사전 설문조사에서 학습자를 분석하였고, 이를 반영하여 프로그래밍 문제를 제시하고 해결하는 과정을 거치면서 다양한 ChatGPT 사용에 대한 분석과 학습자 분석이 이루어졌다. 그 결과 비전공자가 듣고 있는 프로그래밍 수업에서 ChatGPT를 활용하여 얻은 통찰력으로 프롬프트에 필요한 가이드 라인을 마련하였다. 본 연구를 기반으로 향후 비전공자를 위한 파이썬 프로그래밍 수업에서 ChatGPT를 활용한 수업모델을 제시하고 학습자의 피드백 또는 적응형 학습에 활용할 수 있는 방법을 모색할 것이다.

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Method for Measuring Prompt Fission Neutron Energy Spectrum by Means of Threshold Activation Detectors (발단 방사화 검출기를 이용한 핵분열 즉발 중성자 에너지 스펙트럼 측정방법)

  • 노성기;신희성;박종묵
    • Nuclear Engineering and Technology
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    • v.22 no.4
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    • pp.410-415
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    • 1990
  • Prompt fission neutron energy spectrum as a function of energies of neutron inducing fission has been calculated en the basis of the Madland-Nix(MN) model. The resultant spectra have been weighted to excitation functions of $^{27}$ Al(n, $\alpha$), $^{32}$ S(n, p) and $^{115}$ In(n, n') threshold reactions in order to get the average cross sections and then spectral indices which are defined as the average cross section ratio for two selective threshold reactions among the above three. It is appeared that spectral indices together with the neutron spectra are varying with energies of neutron inducing fission. This may indicate that the prompt fission neutron energy spectrum can be determined by measuring experimentally the spectral index.

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Experimental setup for elemental analysis using prompt gamma rays at research reactor IBR-2

  • Hramco, C.;Turlybekuly, K.;Borzakov, S.B.;Gundorin, N.A.;Lychagin, E.V.;Nehaev, G.V.;Muzychka, A. Yu;Strelkov, A.V.;Teymurov, E.
    • Nuclear Engineering and Technology
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    • v.54 no.8
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    • pp.2999-3005
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    • 2022
  • The new experimental setup has been built at the 11b channel of the IBR-2 research reactor at FLNP, JINR, to study the elemental composition of samples by registration of prompt gamma emission during thermal neutron capture. The setup consists of a curved mirror neutron guide and a radiation-resistant HPGe high-purity germanium detector. The detector is surrounded by lead shielding to suppress the natural background gamma level. The sample is placed in a vacuum channel and surrounded by a LiF shield to suppress the gamma background generated by scattered neutrons. This work presents characteristics of the experimental setup. An example of hydrogen concentration determining in a diamond powder made by detonation synthesis is given and on its basis, the sensitivity of the setup is calculated being ~4 ㎍.

Calculation and measurement of Al prompt capture gammas above water in a pool-type reactor

  • Czakoj, Tomas;Kostal, Michal;Losa, Evzen;Matej, Zdenek;Simon, Jan;Mravec, Filip;Cvachovec, Frantisek
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3824-3832
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    • 2022
  • Prompt capture gammas are an important part of the fission reactor gamma field. Because some of the structural materials after neutron capture can emit photons with high energies forming the dominant component of the gamma spectrum in the high energy region, the following study of the high energy capture gamma was carried out. High energy gamma radiation may play a major role in areas of the radiation sciences as reactor dosimetry. The HPGe measurements and calculations of the high-energy aluminum capture gamma were performed at two moderator levels in the VR-1 pool-type reactor. The result comparison for nominal levels was within two sigma uncertainties for the major 7.724 MeV peak. A larger discrepancy of 60% was found for the 7.693 MeV peak. The spectra were also measured using a stilbene detector, and a good agreement between HPGe and stilbene was observed. This confirms the validity of stilbene measurements of gamma flux. Additionally, agreement of the wide peak measurement in 7-9.2 MeV by stilbene detector shows the possibility of using the organic scintillators as an independent power monitor. This fact is valid in these reactor types because power is proportional to the thermal neutron flux, which is also proportional to the production of capture gammas forming the wide peak.

Strategies to improve the range verification of stochastic origin ensembles for low-count prompt gamma imaging

  • Hsuan-Ming Huang
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3700-3708
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    • 2023
  • The stochastic origin ensembles method with resolution recovery (SOE-RR) has been proposed to reconstruct proton-induced prompt gammas (PGs), and the reconstructed PG image was used for range verification. However, due to low detection efficiency, the number of valid events is low. Such a low-count condition can degrade the accuracy of the SOE-RR method for proton range verification. In this study, we proposed two strategies to improve the reconstruction of the SOE-RR algorithm for low-count PG imaging. We also studied the number of iterations and repetitions required to achieve reliable range verification. We simulated a proton beam (108 protons) irradiated on a water phantom and used a two-layer Compton camera to detect 4.44-MeV PGs. Our simulated results show that combining the SOE-RR algorithm with restricted volume (SOE-RR-RV) can reduce the error of the estimation of the Bragg peak position from 5.0 mm to 2.5 mm. We also found that the SOE-RR-RV algorithm initialized using a back-projection image could improve the convergence rate while maintaining accurate range verification. Finally, we observed that the improved SOE-RR algorithm set for 60,000 iterations and 25 repetitions could provide reliable PG images. Based on the proposed reconstruction strategies, the SOE-RR algorithm has the potential to achieve a positioning error of 2.5 mm for low-count PG imaging.

SIMMER-IV application to safety assessment of severe accident in a small SFR

  • H. Tagami;Y. Tobita
    • Nuclear Engineering and Technology
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    • v.56 no.3
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    • pp.873-879
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    • 2024
  • A sodium-cooled fast reactor (SFR) core has a potential of prompt criticality due to a change of core material distribution during a severe accident, and the resultant energy release has been one of the safety issues of SFRs. In this study, the safety assessment of an unprotected loss-of-flow (ULOF) in a small SFR (SSFR) has been performed using the SIMMER-IV computer code, which couples the models of space- and time-dependent neutronics and multi-component, multi-field thermal hydraulics in three dimensions. The code, therefore, is applicable to the simulations of transient behaviors of extended disrupted core material motion and its reactivity effects during the transition phase (TP) of ULOF, including a potential of prompt-criticality power excursions driven by fuel compaction. Several conservative assumptions are used in the TP analysis by SIMMER-IV. It was found out that one of the important mechanisms that drives the reactivity-inserting fuel motion was sodium vapor pressure resulted from a fuel-coolant interaction (FCI), which itself was non-energetic local phenomenon. The uncertainties relating to FCI is also evaluated in much conservative way in the sensitivity analysis. From this study, the ULOF characteristics in an SSFR have been understood. Occurrence of recriticality events under conservative assumptions are plausible, but their energy releases are limited.

Comparison of knife-edge and multi-slit camera for proton beam range verification by Monte Carlo simulation

  • Park, Jong Hoon;Kim, Sung Hun;Ku, Youngmo;Lee, Hyun Su;Kim, Chan Hyeong;Shin, Dong Ho;Jeong, Jong Hwi
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.533-538
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    • 2019
  • The mechanical-collimation imaging is the most mature technology in prompt gamma (PG) imaging which is considered the most promising technology for beam range verification in proton therapy. The purpose of the present study is to compare the performances of two mechanical-collimation PG cameras, knife-edge (KE) camera and multi-slit (MS) camera. For this, the PG cameras were modeled by Geant4 Monte Carlo code, and the performances of the cameras were compared for imaginary point and line sources and for proton beams incident on a cylindrical PMMA phantom. From the simulation results, the KE camera was found to show higher counting efficiency than the MS camera, being able to estimate the beam range even for $10^7$ protons. Our results, however, confirmed that in order to estimate the beam range correctly, the KE camera should be aligned, at least approximately, to the location of the proton beam range. The MS camera was found to show lower efficiency, being able to estimate the beam range correctly only when the number of the protons is at least $10^8$. For enough number of protons, however, the MS camera estimated the beam range correctly, errors being less than 1.2 mm, regardless of the location of the camera.

Performance prediction of gamma electron vertex imaging (GEVI) system for interfractional range shift detection in spot scanning proton therapy

  • Kim, Sung Hun;Jeong, Jong Hwi;Ku, Youngmo;Jung, Jaerin;Kim, Chan Hyeong
    • Nuclear Engineering and Technology
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    • v.54 no.6
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    • pp.2213-2220
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    • 2022
  • The maximum dose delivery at the end of the beam range provides the main advantage of using proton therapy. The range of the proton beam, however, is subject to uncertainties, which limit the clinical benefits of proton therapy and, therefore, accurate in vivo verification of the beam range is desirable. For the beam range verification in spot scanning proton therapy, a prompt gamma detection system, called as gamma electron vertex imaging (GEVI) system, is under development and, in the present study, the performance of the GEVI system in spot scanning proton therapy was predicted with Geant4 Monte Carlo simulations in terms of shift detection sensitivity, accuracy and precision. The simulation results indicated that the GEVI system can detect the interfractional range shifts down to 1 mm shift for the cases considered in the present study. The results also showed that both the evaluated accuracy and precision were less than 1-2 mm, except for the scenarios where we consider all spots in the energy layer for a local shifting. It was very encouraging results that the accuracy and precision satisfied the smallest distal safety margin of the investigated beam energy (i.e., 4.88 mm for 134.9 MeV).

Development of a DDA+PGA-combined non-destructive active interrogation system in "Active-N"

  • Kazuyoshi Furutaka;Akira Ohzu;Yosuke Toh
    • Nuclear Engineering and Technology
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    • v.55 no.11
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    • pp.4002-4018
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    • 2023
  • An integrated neutron interrogation system has been developed for non-destructive assay of highly-radioactive special nuclear materials, to accumulate knowledge of the method through developing and using it. The system combines a differential die-away (DDA) measurement system for the quantification of nuclear materials and a prompt gamma-ray analysis (PGA) system for the detection of neutron poisons which disturb the DDA measurements; a common D-T neutron generator is used. A special care has been taken for the selection of materials to reduce the background gamma rays produced by the interrogation neutrons. A series of measurements were performed to test the basic performance of the system. The results show that the DDA system can quantify plutonium of as small as 20 mg and it is not affected by intense neutron background up to 1.57 × 107 s-1 and gamma ray of 4.43 × 1010 s-1. The gamma-ray background counting rate at the PGA detector was reduced down to 3.9 × 103 s-1 even with the use of the D-T neutron generator. The test measurements show that the PGA system is capable of detecting 0.783 g of boron and about 86.8 g of gadolinium in 30 min.

Analytic simulator and image generator of multiple-scattering Compton camera for prompt gamma ray imaging

  • Kim, Soo Mee
    • Biomedical Engineering Letters
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    • v.8 no.4
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    • pp.383-392
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    • 2018
  • For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.